Electromagnetic vibrators



Aug. 20, 1957 J. URSCHLER ET AL 2 ELECTROMAGNETIC VIBRATORS Filed July 12, 1954 2 Sheets-Sheet 2 ll i 0 INVENTORS 4 JEAN URSCHLER&

CHARLES PATRIS. BY

ATTORNEYS ELECTROMAGNETIC VIBRATORS Jean Urschler and Charles Patris, Toulon, France Application July 12, 1954, Serial No. 442,512

Claims priority, application France July 15, 1953 Claims. (Cl. 310-29) This invention relates to vibrators of the kind comprising essentially a core of magnetisable material, an armature of magnetisable material resiliently mounted at a small separation from the core so as to be vibrated under the effect of varying magnetic fields induced in the core, and an induction coil arranged about the core for producing varying magnetic fields therein. Hitherto the coil has been either (a) directly mounted on the core whereby all the axial and radial vibration of the core were transmitted to the coil, or (b) mounted thereon in such a manner as to be capable of resilient relative axial movement but not relative radial movement, whereby again some vibration at least is still undergone by the coil.

It is found in practice that continued vibration is very detrimental to the structure of such coils and it is accordingly the object of the present invention to provide an improved form of mounting for the coil,'with respect to the core and armature, whereby the coil is resiliently suspended as regards both axial and radial movements of the vibrating members and is thus substantially unaffected by vibration.

In the accompanying drawing, illustrating by way of non-limiting example two embodiments of theinvention:

Fig. 1 represents, in longitudinal section, a first embodiment of vibrator the coils of which are mounted in accordance with the invention.

Fig. 2 represents the same device seen in transverse section.

Figs. 3 and 4 show a second embodiment of vibrator seen respectively in longitudinal and transverse section.

In Figs. 1 and 2, the vibrating device is constituted by an armature 2 fixed on a vibrating plate 3 by brackets 6, the vibrating plate being supported by any suitable known structure (not shown) in position above the core 1. The armature is disposed above the laminated core 1 of soft iron in the form of a U. A gap 7 is formed between the core 1 and the armature 2, and permits the vibrating plate 3, and the mounting 4 on which the core 1 is fixed by screws 5, to vibrate freely.

The resilient support between the vibrating plate 3 and the mounting 4 is arranged in such a manner that under the normal load the vibrating plate 3 will be in mechanical resonance withthe desired frequency.

The inductance coils 8 are wound on an insulating spool member 11 having end plates 9 and 10. The insulating spool 11 is disposed with play about the arms of the core 1 in such a manner as not to be in contact therewith at any point and is thus free to move both radially and axially within limits.

The end plates 9, are retained in position by rods 16, and ring screws are disposed thereon and also on the vibrating plate 3 and on the U-shaped mounting 4. Springs 14 are engaged into the eyelets of these ring screws 15 and support the coils 8 in resilient manner.

The floating system is constituted by the coils 8 and the springs 14 are arranged and dimensioned in such a manner that its inherent resonant frequency is consider- 2,303,762 Patented Aug. 20, 1957 CCw - ably lower than the frequency of vibration of the apparatus. Supports of rubber (not shown) could replace the springs 14.

The vibrating device of Figs. 3 and 4 is constituted by an armature 18 provided with recesses 19, 20 having shoulders receiving the relatively weak compression springs 21, 22. The lower part of the armature comprises recesses 23, 24 with shoulders 25, 26 receiving springs 27, 28 of greater strength. Guides 29, 30 are coupled by a cross-bar 34 secured thereon by nuts 33, said cross bar bearing against the upper springs 21, 22. The movable core 35 is bolted on the armature 18 and the core 38 is soldered to the plate 31. A flexible joint 39 completes the assembly. In Fig. 4, annular end pieces 40 of resilient material provide elastic support for the floating coil which can move radially and axially with respect to the core 38.

By tightening the nuts 33, and compressing the springs 20, 21, adjustment of the gap 41 can be eifected. Under the effect of induction, the core 35 is attracted to the core 38, and when induction lessens, the springs 27, 28 force the cores apart again.

What we claim is:

1. A vibrating device comprising a core assembly including a mounting and a core of magnetisable material secured at one end thereon, an armature of magnetisable material disposed adjacent the other end of the core leaving a small gap between the armature and core, means resiliently supporting the armature adjacent the core whereby the armature may vibrate under the efiect of varying magnetic fields induced in the core, an inductance coil disposed about the core and spaced therefrom, a first set of tension springs connected between the coil and the armature, and a second set of tension spring connected between the coil and the mounting, whereby the coil can move resiliently radially and axially with respect to the core and armature.

2. A vibrating device comprising a core mounting having two parallel spaced members, a core of magnetisable material secured on one said member, an armature disposed between the parallel spaced members and resiliently supported at a small distance away from the core by a first compression spring means arranged between the armature and the first spaced member and a second compression spring means arranged between the armature and the second spaced member, whereby the armature may vibrate under the effect of varying magnetic fields induced in the core, an inductance coil disposed about the core and spaced therefrom, and resilient mounting means arranged between the coil and the armature and between the coil and the second spaced member, whereby the coil can move resiliently radially and axially with respect to the core and armature.

3. A vibrating device, as claimed in claim 2, including means for varying the separation of the first and second spaced members for adjustment of the gap between the armature and core and for varying the natural frequency of the armature by varying the loading of the compression spring means.

4. A vibrating device comprising a core of magnetisable material, an armature of magnetisable material disposed adjacent the core leaving a small gap between the armature and core, means resiliently supporting the armature adjacent the core whereby the armature may vibrate under the effect of varying magnetic fields induced in the core, an inductance coil disposed about the core and spaced therefrom, and means resiliently cou pling the coil respectively to the core and to the armature and acting both radially and axially of the coil to allow resilient radial and axial movement of the coil with respect to the core and armature.

2,803,762 9 .5. A vibrating device, as claimed in claim 4, wherein the dimensions and Weight of the coil and its resilient coupling means are so arranged that the natural frequency of the coil and coupling means is less than the operating frequency of the vibrating device. 5

References Cited in the file of this patent UNITED STATES PATENTS 

